Re: [PATCH 05/33] arm: omap: board-cm-t35: use generic dpi panel's gpio handling

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

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On 2013-02-14 08:56, Igor Grinberg wrote:
> On 02/13/13 17:59, Tomi Valkeinen wrote:

>> Okay, so I just realized there's an spi backlight driver used here, and
>> that backlight driver is actually handling the SPI transactions with the
>> panel, instead of the panel driver. So this looks quite messed up.
> 
> Yep, it always was.
> The whole DSS specific panel handling inside the
> drivers/video/omap2/displays is a mess.

Well, that's not mess itself, it's just omap specific panel framework.
But dividing single device handling into two separate places is a mess.

> Those panels can be (and are) used not only with OMAP based boards.

True, but as there's no generic panel framework, that's the best we can
do. But see CDF (common display framework) discussions if you're
interested in what's hopefully coming soon.

>> For a quick solution, can we just set the LCD_EN at boot time (with the
>> msleep), and not touch it after that?
> 
> That would be sensible for now, so this series can be merged.
> As a more appropriate (and long term) solution,
> I plan on moving the panel reset pin handling to the spi backlight
> driver itself.

Well, if you must. But I suggest moving the whole panel handling into a
(omap specific) panel driver, as it's done for other panels. That way
you'll have a proper panel driver for it, for omap, and when CDF comes,
you'll get a platform independent panel driver for it.

Of course, if you have multiple platforms already using that backlight
driver, the omap specific approach may not be enticing. So perhaps it's
easier to just do the quick fix and wait for CDF.

 Tomi


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